package com.hmdp.utils;

import com.hmdp.common.constant.RedisConstants;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

/**
 * @author 计算机系 ITAEM 摆渡人
 * @description
 * @date 2022/11/2 19:47
 */
@Component
public class RedisIdWorker {

    //开始时间戳
    private static final long BEGIN_TIMESTAMP = 1640995200L;
    //序列号位数
    private static final long COUNT_BITS = 32;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    /**
     *
     * @param keyPrefix 业务前缀
     * @return 全局唯一id
     */
    public long nextId(String keyPrefix){
        //1.生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timestamp = nowSecond - BEGIN_TIMESTAMP;

        //2.生成序列号
        //2.1获取当前日期，精确到天
        String day = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        //2.2自增长
        long count = stringRedisTemplate.opsForValue().increment(RedisConstants.ICR + keyPrefix + ":" + day);

        //3.拼接并返回
        return timestamp << COUNT_BITS | count;
    }
}
